There was once a leopard in the jungle; and a very nocturnal leopard he was too. He could hardly sleep at night and, lying on a branch of his magnificent tree, he spent his time watching what was happening in the forest at night. This is how he came to learn that there was a thief in that forest. He would watch the thief go out every night with empty hands and return loaded up with his stolen loot. Sometimes the thief had nabbed the senior monkey's bananas, other times he had filched the lion's wig, or pinched the zebra's stripes. One night he even snuck home with the big elephant's false tusk, which the elephant had been secretly wearing for quite some time. However, as the leopard was a very quiet sort of cat, who lived at the margin of everything, he didn't want to say anything to anyone. He didn't see it as his business, and, if truth were told, he rather enjoyed discovering these little secrets. And so, thanks to the stealthy thief, quite a stir was being created in the world of the animals: the elephant felt ridiculous without his false tusk, and the zebra now looked like a white donkey, not to mention the lion who, now as bald as a lioness had lost all respect. Most of the other animals were in some similar position too. They were furious, confused or ridiculous, but the leopard lay quietly in his tree, each night enjoying the thief's escapades. However, one night the thief went on vacation, and after having waited a long while for him to appear, the leopard grew tired and decided to sleep for a while. When he woke up he found himself in a place very different from his usual tree, he was floating on the water of a small lake inside a cave, and around him he could see all those objects which, night after night, he had seen being stolen… the thief had cut down his tree and stolen his entire home along with the leopard himself! Well this was the last straw, so the leopard, taking advantage of the thief not being there, ran out and went straight to see the other animals to tell them where the thief had hidden all their things… they all praised the leopard for having discovered the thief and his hideout, and allowing them to recover their possessions. In the end, the animal who lost most from all this was the leopard, who couldn't replant his magnificent tree and had to make do with a much inferior tree located in a very boring site… and he regretted having not been concerned at the problems of the other animals, now seeing that in the long run those very problems had become his own. 
Indifference to the problems of others can allow those problems to grow until they end up being problems to ourselves. 